People use the aftermarket mounts so that they don't have to do any custom work. If you use OEM mounts for a b-series swap (I assume that is what you're talking about), you have to reweld the mount locations in the engine bay.
i got ls mounts in my 91 ef hatch..with a custom made front mount...u gotta remember that a b16 probably has almost twice the hp of ur previous motor...and its in a really light car..so there is always gonna be vibration...mine has vibration but its not bad at all..i actually wanna put stiffer inserts in it...helps for the launch...anyways after a while ur gonna get used to the vibration and u wont even notice it....i also wanna put one of those engine dmpeners..has anyone seen these?? ive heard nothin but good things about em and they are only like 100 bux
I had my mounts re welded in my rex. I was told the stock mounts are fine. My friend is running 500hp in his with the stock mounts and his engine sits just fine. Dont the poly mounts send more vibes into the car though?
Yeah using inserts will most likly increase vibrations. But hell Im young I can put up with it, when I want a easy ride Ill get a Volvo. Speaking of inserts Ive heard of people using the epoxy stuff used for attatching a wind shield to a car to fill there motor mounts. Seems like a pretty easy cheap thing. Just an Idea.